EFFECT OF BUSH BURNING ON INFILTRATION CHARACTERISTICS AND CEMENTING SUBSTANCES OF SOIL AGGREGATES ON SOILS DERIVED FROM COASTAL PLAIN SANDS IN AKWA IBOM STATE A RESEARCH PROJECT BY JOHN, ANYANIME ANIEDI 05/AG/SS/155 TO DEPARTMENT OF SOIL SCIENCE FACULTY OF AGRICULTURE UNIVERSITY OF UYO, UYO IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF B.

AGRIC DEGREE (SOIL SCIENCE) FEBRUARY, 2012 CERTIFICATION This is to certify that this work was carried out by John, Anyanime Aniedi in the Department of soil Science, University of Uyo, Uyo. Mr. I. D. Edem…. …………….

. Supervisor Date Dr. Peter I. Ogban….

………….. Head of Department Date Prof. E. S. Udoh …. …………….

. Dean, Faculty of AgricDate Pro. E. T. Eshett…. …………….

. External Examiner Date DEDICATION This project is dedicated to God Almighty, my parents, (Late, Elder Aniedi J. Udoh) and May His gentle soul rest in perfect peace, Amen, and Priest Ima-obong Aniedi John for their love, care and inspiration towards my academic pursuit. ACKNOWLEDGEMENTS May glory, honour and adoration be to God Almighty who supplied all my need and everything that this work needed, without this divine provision and support, this research project would not have been possible.I am sincerely grateful to my supervisor Mr.

I. D. Edem for his invaluable contributions to the success of this research project. My thanks go to my head of Department Dr. P. I. Ogban and to my lecturers Dr.

D. J. Udoh, Dr. B. T.

Udoh, Dr. G. S. Effiong,Dr U. Udoinyang, Dr. J. Obi, Mr.

P. E. Usuah and Mr. U. Akpan for their assistance and advice. My sincere gratitude also goes to Mr.

U. A. Udoinyang, Department of Animal Science. My thanks goes to staff of the Department of Soil Science for their co-operation and assistance, particularly Mr.Ini Obot and Mr. A. D.

My special thanks to Emmanuel Udo, Emem Asubop, Idariest Obott, Ima-obong Fabian, Itoro Ekpo, Juliet Abel, Ndifereke Awak, Eyakeno Luke, Ini-obong Edem, Utibe, Nkese Obot for their co-operation, and advices during my research project.Finally, I express my appreciation to all who may not have been mentioned above, but contributed directly or indirectly to the success of this research project, may God Almighty bless you all. John, Anyanime Aniedi ABSTRACT This research was conducted to assess the effect of bush burning on infiltration characteristics of coastal plain sands in Akwa Ibom State, Nigeria.

The study location was the University of Uyo Teaching and research farm, Use-Offot, Uyo. Three plot measuring 10m x 10m each was marked out, different level of treatment imposed on each of the plot.The treatment was replicated making it a total of nine sub-plot.

Nine mini-profile pit were sited at representative position along the geomorphic surfaces and soil samples were collected at the preburnt plot and the post burnt plot and analysed. Infiltration was also conducted beside each of the replicated profile pit at the preburnt and post burnt plot. The infiltration run was conducted using the double ring infiltrometer. From the cumulative water intake, sorptivity and transmissivity were derived using kostiakov’s equation. The result revealed that the study area was loamy sand in texture.These soils were dominated by sand fractions with mean 832.

97 gkg-1 at the surface and 816. 00 gkg-1 at the subsurface. Organic matter before burning was 1. 89 at the surface and 1. 44% at the subsurface. After burning 20 kgDm/m2 has 2. 01% (surface) and 0.

0Summary and Conclusion ——–50 References————52 Appendixes LIST OF TABLES Pages Table 1:Physical Parameters ——–28 Table 2: Chemical Parameters ——–36Table 3: Table Comparison of Infiltration Characteristic at Different heating intensities Along the Slope 44 Table 4: Correlation Matrix for Control Plots47 Table 5: Correlation Matrix for burned Plots48 CHAPTER ONE 1. 0Introduction Infiltration is the gradual entering of water into the soil. It is said to be a surface phenomenon since water can enter the soil horizontally or by capillary rise. Infiltration process is dynamic and complex and varies with several soils, vegetative and climatic parameter affecting soil water conservation, management and agricultural land use according to Edem (2007).Infiltration is the rate at which water enters the soil through its surface, it is mainly by attraction of water held in pores and soil (that is, by the difference water and the low matrix potential of water held in pores and attached to surface in the soil).

However, gravitational force helps in pulling the infiltrating water downward. This driving force or average potential gradient decline, when the water has to flow further to extend the wilting point.Infiltration is a pivotal process in landscape hydrology that greatly influence the moisture regime for plants and its determines the amount of run off which will form over the soil surface.

Infiltration process is a complex interaction process of many factors. The most basic factors are physical and chemical properties of the soil and rainfall. The soil factors that influence infiltration are soil texture, structure, organic matter content, depth to impermeable layers, density and also chemical or biological characteristics of the soil (Babalola, 1978; Goldman et al. , 1986) as cited by Ogban and Ekerete (2001).

These properties affect soil infiltration both from the standpoint of irrigation, drainage and erosion. However, high infiltration rate must be encouraged as it is not only increasing the amount of water stored in the soil for plant use, but also reduces flood threats and erosion resulting from runoff. Coastal plain sand parent material soils in Akwa Ibom State are used for crop production but at traditionally subsistence scale. The soil need to be properly evaluated interms of infiltration characteristics to provide data that would guide soil and water management or conservation and increase agricultural production.During wet season where there is an erratic distribution of rainfall, water stress is being experience at times by crops. The degree of infiltration rate however, varies from one soil to the other, therefore, in order to achieve all year round crop production, infiltration behavior of the soil must be accurately quantified so that during the short rainfall and also during wet season, soil condition can be improved so that water can infiltrates through the soil for effective used by plant.

Additionally, fire may also influence the rate of infiltration and soil physical properties.Soil texture, structure, porosity, wetability, infiltration rate and water holding capacity may be affected by burning. The extent of fire effects on these soil physical properties varies considerably depending on fire intensity, fire severity and fire frequency. According to Hungerford et al.

6mm diameter). Soil porosity can also be reduced by the loss of soil invertebrates that channel in the soil.There is no doubt that fire has a dramatic influence on the soil macro and micro nutrient, forest fires whether planned or not usually decrease the total site nutrient pool (the total amount of nutrient present) through some combination of oxidation, volatilization, ash transport, leaching and erosion. A low intensity slash fire resulted in the following reductions in understory and forest floor nutrient pools: 54-75% of N, 37-50% of P, 43-60% of K, 31-34% Ca, 25-49% mg, 25-43% of Mn (micronutrient, and 35-54% of B (micronutrient) (Raison et al. , 1985) some nutrient dynamics are more sensitive to fire than others.

The concentration of potassium, calcium and magnesium ions the soil can increase or be unaffected by fires where as nitrogen and sulphur often decrease. Nutrient for example being volatilizing out of organic matter at only 2000C, whereas calcium must be heated to 1200C for vaporization to occur (Neary et al. , 1999). Nutrient are abundant in organic soil layers, and the amount of these layers consumed is proportional to fire intensity, this will also affect the rate of infiltration (that is the measure of the rate at which soil is able to absorb rainfall or irrigation).Many forms of equation have been proposed for simulating infiltration of water into the soil, from those that are strictly empirical to those that are deemed to be mechanistic (Haver Kamp et al.

, 1988). One of the most popular empirical models used for this simulation is the kostiakov’s equation (Kostiakov, 1932). Kostiakov equation has been shown to satisfy the evaluation, consider used in predicting and controlling rain water infiltration in crop and rangeland, better than other equation (Dixon et al. , 1978).This has been attributed to its simplicity and application under wide range of condition (Ghosh, 1985). Therefore, the objective of the study are; 1.

To assess the infiltration characteristics of coastal plain sand with respect to the physical and chemical properties of the soil. 2. To assess the effect of temperature on the infiltration characteristics of coastal plain sand.

3. To evaluate the effect of fire on the cementing substance of aggregate as it relate to the rate of infiltration. CHAPTER TWO LITERATURE REVIEW 2.

1INFILTRATIONInfiltration is the vertical intake of water into the soil through the surface Edem ( 2007). Usually at the soil surface, the measurement of infiltration rate form a vital part of many surveys involving irrigation development or soil conservation. The process of water infiltration is a physical one. There has been attempts by different researchers to describe the process. Many forms of equations have been proposed for infiltration of water into the soil, from those that are strictly empirical to those that are deemed to be mechanistic (Haverkamp et al.

1988). One of the most outstanding and popular models used for the simulation is the Kostiakov equation (Kostiakov, 1932). Apart from Kostiakov equation, other researchers have researched into this and gave some models to use in determining this. A typical example is the comparison that Swartzendruber and Youngs (1974) made to compared three physically based infiltration equations and concluded that Philips two-term equation is preferred over Green and Ampt’s and a linearised form of Philips equation.

Ghosh (1980) proposed a model combining Philips two-term and Kostiakovs equation to minimize the limitations of both models. However, a predetermined (or measured) saturated hydraulic conductivity is required for such a model. According to Fahad et al. , (1982) who studied the effect of soybean and other cropping sequences on infiltration, Philip’s and Kostiakov’s equations simulated field data reasonably well and that Kostiakov’s equation provided a better fit for the early and late stage of infiltration.

Kostiatov’s equation has been shown to satisfy the equation used in predicting and controlling rain water infiltration in crop and rangelands, better than other equations Dixon et al, (1978). This has been under wide range of conditions Ghosh (1985). Cook et al. , (1982) studies the infiltration process on reclaimed surface mined soils using Horton’s , Philip’s Green and Ampt’s and Parlange’s equation. They reported that these models generally failed to predict initial infiltration rates adequately, although, they did simulate long-term infiltration rates relatively well.

High infiltration rate can be obtained when macrospores are open to the soil surface (Beven and Germann, 1982) during pounded conditions. Soil management has been found to have a more pronounced effect on infiltration than soil type. Mudiare and Adewunmi (2000) evaluated the Talsma-parlange (1972) model for four soil units ranging from sandy loam to loam soils in a certain part of the country (specifically Jigawa State) and found that the models was adequate in predicting water infiltration to a reasonable level of accuracy.In the study reported herein the performances of six infiltration models were evaluated on soils formed on Sandstone/Shale parent materials. Research shows that there are some factors affecting infiltration characteristics include soil texture, porosity, Aggregate stability, Bulk density, and organic matter. Some researchers have made considerable researches to show how these affect the infiltration capacity of the soils.

2. 2FACTORS AFFECTING INFILTRATION Infiltration of water depends on several soil physical parameters and other factors associated with water application characteristics.Most of these parameters operate at or near the soil surface. Soil Texture There is no doubt that soil texture and the amount of water in the soil are interrelated since they influences infiltration process. Water infiltrates much faster through course textured soils than fine textured soils, this is because coarse textured soil have more macrospores than fine textured soils. Fine soil particles tend to be very close to each other hence are dominated with microspores.

Soils with high context of expanding clays may have a very high initials infiltration rate as water pour into the network of shrinkage cracks (Brady and Well, 1999). Also, texture influences soil behavior through its specific surface which most of the physico-chemical processes that determined the soil behavior depend on the different textural fractions, impacts on the soils will occur through inter-particle pores, fine textured clays and loams soils are compacted through traffic and or tillage, soil aggregates are broken down resulting in dramatically reduced infiltration rates.Kohnke (1986) as cited by Babalola (1987) had reported that infiltration rate on a loamy sand soil could be at least 20 times higher than on a clay loam soil, all other conditions being equal and that infiltration capacity decreases with increasing fineness of the soil. Porosity Porosity is one of the factors affecting the rate of water infiltration into the soil. This porosity is changed by cultivation or compaction. Cultivation influences infiltration rate by increasing the porosity of the surface soil and breaking up of the surface seals Michael (1999). The distribution of pores also has a great influence on water infiltration.

In a soil profile where there is predominance of macrospores, the soil will have high infiltration capacity. According to Obi and Akamigbo (1981) low infiltration rates in the flood plains in Nigeria is as a result of the predominance of micro pores. Edwards et al. , (1988) also observed that during ponded infiltration, water moves rapidly through vertical continuous macrospores formed from earthworm channels and Grismer (1986) Indicated that changes in infiltration rate with time largely depends on corresponding changes in the distribution of the water conducting pores than the total pore space per seconds.Aggregate Stability Soils are mostly characterized by three outstanding materials, the sand, silt and clay. The coming together of these materials is called aggregation. Aggregate stability is therefore, the strength of soil structure against mechanical manipulation.

Soils that have stable strong aggregates as granular or blocky structure have a higher infiltration rate than soils that have a weak, massive or plate-like structure. Esu (1999) reported that a well aggregated soil is often well drained, and has good permeability of water, air and root.The stability of the soil influences the movement of water into the soil, therefore, than soils with less stable aggregate. The role of soil organic matter to improve aggregate stability has been reported by Channel and Swift (1984). Aggregates and structural stability help in maintaining good pore size distribution in the soil.

When a soil is stable structurally, there is a formation of pores, which helps in infiltration process of water into the soil horizon. This shows that the larger the aggregation of the soil particles, the higher the infiltration capacity of the soil. Bulk DensityAs a basic soil physical property, bulk density is the mass per unit volume of oven dry soil and this includes both solids and pores. For a given soil, it indicates how compacted or loose a soil is. According to Hilner (1981), compacted soils restrict water movement into the soil, limits water storage and inhibit root penetration, proliferation and impede drainage. Increase in bulk density of a given volume of soil will decrease the total pore spaces and reduce the amount of water infiltrating the soil. Bulk density is greatly influenced by the cropping and soil management practices.

The effect of tillage on infiltration usually lasts only until the soil settles back to its former condition of bulk density because of subsequent irrigations Michael (1999). 2. 3EFFECTS OF FIRE ON INFILTRATION CAPACITY OF THE SOIL The transfer of heat to soil (e. g. by fire) is the main mechanism which constitutes high temperatures and thus affect the physical, chemical and biological properties (Neary et al. , 1999).

By altering soil structure severe fire can increase soil bulk density (DeByle 1981), and reduce soil porosity (Wells et al. , 1979), mostly through the loss of macropores (Wells et al. , 1979), mostly through the loss of macropores (>0. 6mm diameter). Intense fires (>4000C) may also permanently alter soil texture by aggregating clay particle into stable sand sand-sized particles making the soil texture and more permeable to the air and water.Intense burning also induce the formation of water repellent soil layer by forcing hydrophobic substance in litter downward through the soil profile.

These hydrophobic organic compound and coat-soil aggregate mineral creating a discrete layer of water repellent soil parallel to the surface. According to Neary et al. , (1999) water repellent are formed between the temperature of 176-2880C and destroyed at higher temperature (>2880C). Extensive water repellent layers and block water infiltration contribute to runoff and erosion fire induced changes in soil structure and texture, it can potentially impair soil hydrology.Decreased soil porosity and the formation of water repellent layers decreased water infiltration rate (Neary et al. , 1999). Loss of soil organic matter and increased bulk density can decrease the water storage capacity of the soils.

CHAPTER THREE MATERIALSAND METHODS 3. 1EXPERIMENTAL STUDY AREA The study was conducted at the University of Uyo Teaching and Research farm, Use Offot Uyo, Akwa Ibom State, South Eastern Nigeria. The area, is located between latitude 400 301 and 50 3’N and 20’E and attitude 65m from sea level.

3. 2CLIMATE AND VEGETATIONThe area is divided into two distinct season, the wet or rainy and dry seasons. The wet or rainy season begins form April and lasts till October. It is characterized by heavy rainfall of about 2500 – 4000mm per annum (Peters et al. , 1989). The rainfall intensity is very high and there is evidenced of high leaching and erosion associated with slope and other rainfall factors in the area.

The dry season starts from November and lasts till March of which period is characterized by high temperature with a mean annual temperature of 28°C.The highest temperature is often experienced between January through March, the period described by Enwezor et al. , (1990) as overhead passage of the sun.

The relative humidity is between 70% and 80%. The landscape is generally undulating to steep hills while the vegetation is mainly, the tropical rain forest. The soils are derived from sandy parent materials which are weathered with low activity clay (Udo and Sobulo, 1981). The predominant land use is continuous cropping.

The prevalent vegetation in the area is Panicum maximum and imperial cylindrical. 3. 3FIELD STUDY Site Selection and Land PreparationThe selected area was divided into three (3) plots each measuring 10 x 10m2 with three replicates making a total of 9 sub-plots with the slope of 0 to 2 percent which is not easily eroded was selected for the study. The land was cleared using Machete and the trash was left on the surface of the ground for a week for it to dry. 20, 60 and 120 kg/m2 of the dry biomass was measured using measuring scale and was imposed on the respective replicated plots to produce three levels of fire intensities. Pre-and -Post Burnt Soil Samplings Nine Mini-profile pits each of 50cm depth was dug at the centre of each of the 9 replicates or sub plots.

Bulk, core and aggregate samples were collected at two depths of 15cm interval (0-l5 and 15-30cm), before and after passage of fire. The core samples were obtained for saturated hydraulic conductivity and bulk density determinations. The soil samples were secured in a core and one end of the core was covered with a piece of calico cloth fastened with a rubber band and properly labeled while the bulk samples were collected and secured in a properly labeled polythene bags before it was conveyed to the University of Uyo soil science laboratory for physical, chemical and structural parameters determinations. . 4PERFORMANCE OF EXPERIMENTAL FIRE, THERMAL RESULTS AND DETECTION OF EMITTED GASES The experimental fire with measured dry biomass was performed.

The atmospheric pressure and air temperature were taken and the relative humidity determined when the winds were calmed. The maximum temperatures reached during the fires were recorded by means of soil thermometer, while the gas fluxes were measured with hand-held gas detectors. 3. 5INFILTRATION RUN Infiltration run was carriedout beside each of the replicated profile pit using the double ring infiltrometer method by FAO, (1979).The infiltrometer has an outer ring of 55cm diameter and inner ring of 30cm diameter. This were driven concentrically into the soil to a depth of 15cm using the driving plat and mallet.

The soil surface within the ring will be covered with dry grass to protect it from direct water splash. Infiltration was commence by adding water into the outer ring and the water was allowed to infiltrate into the soil. This act as a buffer to discourage lateral flow of water, but rather encourage one-dimensional vertical flow of water in the inner ring.

This was immediately followed by the addition of water to a depth of 15cm in the inner ring. Reading was taken only from the inner ring with the use of ruler taped attach to the inner ring reading was taken at 1 minute, 2 minutes, and 5 minutes depending on the soil texture. The generated data was used to calculate the infiltration at 1 minute and 2hours and other infiltration characteristics. The data were into Kostiakov’s (1932) and Phillip’s equation (1957) to determine the infiltration characteristics of the soil.

3. 6LABORATORY ANALYSIS Soil Sample PreparationsIn the laboratory, the core samples were placed in a basin of water and allowed to saturate by capillarity for 24 hours while bulk samples were spread on clean papers and allowed it to air dried for about two days. The dried soil samples were ground using agate mortar and pestle and 2mm sieve was use to sieve the samples. The sieve samples were used for both mechanical and chemical analysis. Determination of Saturated Hydraulic Conductivity (Ks) Saturated hydraulic conductivity was determined using constant head parameter method according to Day’s procedures (White, 1986).

The saturated core samples were placed in funnel, resting on a tripod stand after the constant head cylinder was placed on top of it and fastened together using marking tape: A constant head of water was maintained throughout the period of the experiment. The flux of water passing through the soil column was collected in a measuring cylinder and readings were attended in each of the samples. Calculation Ks = QL At? H Where; Ks saturated hydraulic conductivity (cm/hr) Q = effluent discharged (cm3) A = Hr2 cross sectional area of core cylinder (cm2) = Pie = 22/r or 3. 142 r = radius of the core L = Length of the soil column (cm) H= Height of water above the soil column ?H= HA – HB = hydraulic head difference between top and down bottom of the cylinder (cm) HA=h + L HB=O + O Estimation of Bulk Density and Total Porosity Bulk density was estimated by dividing the oven dry mass of the soil by volume of the soil as described by Grossman and Reinsch (2002). BD = Ms Vt Where: BD = Bulk Density (g/cm3) Ms = mass of oven-dried soil samples (g) Vt = total volume of soil (cm3), (solid + pores)The total volume of the soil was calculated from the internal diameter of the core cylinder. Total porosity was calculated from bulk density assuming particle density of 2.

4. 1 Soil pH Soil pH was determined in 1:2. 5 soil water suspension measured using a glass electrode pH meter as described by Thomas (1982).

3. 4. 2 Determination of Electrical Conductivity (EC) Electrical conductivity was determined by using electrical conductivity electrode. This was done by inserting the electrode into the same soil solution that was used to test for pH. 3. 4.

3 Determination of Exchange Acidity The exchange acidity was extracted with INKCL solution. The total acidity from the exchangeable hydrogen and aluminum were determined by titration as described by IITA (1979). 0m1 of the extract was pipetted into a 250m1 conical flask and 20ml of distilled water and five drops of phenolphthalein indicator were added to the solution the solution was titrated with 0.

6 Organic Carbon Organic carbon was determined using wet oxidation method of Walkey and Black (1934) as modified by Nelson and summers (1996). 3. 4. 7 Determination of Total Nitrogen Total Nitrogen was determined by Macrokjeldah digestion method (Bremmer, 1996). Carbon: Nitrogen was calculated by dividing organic carbon by total nitrogen. 3.

4. 8 Determination of Available PhosphorusThe available phosphorus was determined using Bray P-1 method of Bray and Kurt (1945) as described by Murphy and Riley (1962). 3. 4.

9 Estimation of Base Saturation Base saturation was determined by dividing the total exchangeable bases by effective cation exchange capacity and multiplying by 100. Base saturation (%) = x TEB 100 (%) CEC 1 CHAPTER FOUR RESULT AND DISCUSSION 4. 1PHYSICAL PROPERTIES The physical properties of the study area as shown in Table 1 was grouped based on different level of treatment i. e. 20 kgDm/m2, 60 kgDm/m2 and 120 kgDm/m2.The result is as follows: 4.

1. 1Particle Size Distribution Coarse sand fraction (CS) was 408. 57 gkg-1 at the surface and 147. 60 gkg-1 at the subsurface before burning. After burning, 20 gkg-1 has a CS range of 515.

Silt content before burning was 37. 00 gkg-1 at the surface and 50. 30 gkg-1 at the subsurface.

After burning it was 267. 30 ± 1. 420 gkg-1 at the surface and 868. 70 ± 2. 749 gkg-1 at the subsurface for 20 kgDm/m2.

For 60 kgDm/m2, it is 61. 30 ± 1. 420 gkg-1 at the surface and 133. 53 ± 2. 157 gkg-1 at the subsurface. For 120 kgDm/m2, it was 608. 00 ± 1.

420 gkg-1 at the surface and 100. 20 ± 2. 749 gkg-1 at the subsurface. Before burning, clay content was 127. 00 gkg-1 at the surface and 133. 0 gkg-1 at the subsurface. After burning, for 20 kgDm/m2, it was 117.

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